One of the inventors in this application is a physician, who is a plastic and reconstructive surgeon and a wound healing specialist practicing for more that twenty-five years. In his practice he has encountered, studied, and treated all wounds on every location of the human body. His experience confirms that, whatever the mechanism of action, surgical, traumatic, neo-plastic, arterial disease, venous stasis, lymphatic, pressure, infectious, caustic, thermal, hypothermal, infarction, or (strangulation), every and all wounds are the direct result of the disruption of the circulatory system.
Further, this one inventor has been a horse owner and rider for all of his adult life. He has first hand knowledge of the condition of laminitis in horses. Over a period of fifteen years, he has made numerous attempts through consultations with veterinarians, attendance at conferences on the subject and a reading of the literature in an effort to find the underlying cause of the condition, the mechanism of injury, and perhaps a cure for the condition which baffles the equine world and the second largest cause of euthanasia in horses.
In his own experience he has personally cared for his own horse and has shepherded her through at least six episodes of this condition which almost took her life. This has led him to conclude that laminitis, with its multiplicity of purported causes, must be treated aggressively, early, and with a multiplicity of modalities.
As noted above, this one inventor has been involved in plastic and reconstructive surgery. He is a wound care specialist involved in the healing of wounds of all types. He has treated patients with vascular extremity wounds and having made the comparison with the human model, he has applied it to the equine model. This inventor concludes that it is clear, as now documented in the literature, that laminitis is a vascular disease occurring at the arteriovenous junction within the confines of a closed space—the hoof.
Laminitis is defined as the debilitating persistent and chronic condition of horses' hooves, which occurs when a critical mass of the interwoven complexes of connective tissue and blood vessels which hold the distal phalanx, P3, (coffin bone), to the inner surface of the keratinized hoof, fail to function. This is the result of a number of systemic and physiological causes. The attachments separate, become “devascularized” and detach from the hoof's inner wall. The strong pull of the deep flexor tendon on the coffin bone and the combination of the weakened attachments, causes the bone to rotate downward creating severe pain, edema, venous congestion and lymphedema and significant debilitation. When left unchecked, this condition results in “founder” an old term for exposure of the coffin bone, through the sole of the hoof. This most commonly renders the animal unable to survive and usually results in euthanasia.
In his human practice the one inventor has used a variety of compression devices to alleviate the problems of venous stasis, peripheral vascular disease and lymphedema with great success. These treatments of the human condition are well described in the literature and proven by evidence-based studies. It has been shown that venous stasis and increased pressure in the extremity, as a result of incompetent valves and shunting of the blood to the level of the skin, causes pressure ulcers. Because the skin is expandable living tissue, the increased pressure impinges on the sub-dermal plexus of the skin and causes a breakdown resulting in an ulcer.
The incompetent valves and venous congestion cause dilation, pressure, and cause proteinaceous material to leak into the extra cellular and sub-cutaneous tissue, (a so-called “third space”) resulting in more edema obstruction of the lymphatics. This causes extremity swelling and tightening of the skin to maximum expansibility, thus impeding the arterial flow to that extremity. Peripheral vascular disease i.e. arterial inflow obstructions, causes severe pain, anoxia, swelling and compromise to the overall vascular flow to the extremity. The anoxia to the tissue causes lactic acidosis build up, cramping, electrolyte imbalances, cellular destruction and severe pain.
The external compression devices currently on the market, to some degree, decrease the congestion, drive the third space proteinaceous material and lymphatic drainage back into the venous system, relieving the skin of pressure, and improving the condition of wounds. All of these external devices mimic the return flow of the venous system as well as decompress and mobilize the third space edema. The decompression of the lymphatic system thus reduces the overall pressure on the arterial system. This is all achieved by improving the gradient between the arterials and the venules, thus improving the overall extremity flow, oxygenation and wound healing. Oxygenation and arterial flow is necessary for all wounds to heal. Venous stasis in tissue can destroy an extremity. A long recognized modality of venous decompression used for centuries is the application of leeches, which allow for continued arterial flow increasing oxygenation.
If we extrapolate the human model to the equine model the exact same venous and arterial congestion occurs with the disruption of the arteriovenous system in the hoof. This inhibits osmotic transmission and once the continuum is broken and the hemodynamic equilibrium is affected, the attachments to the hoof wall tear. With the tearing there is a high probability of hematoma. With a clot formation further increasing the pressure, the arterial side becomes compressed also failing to deliver oxygen. Edema results, causing pain thus setting up the cycle of pain, edema, compression and more pain.
It is the result of the changes in the hydrostatic pressures that causes the tearing of the lamellae. This occurs within the closed space of the hoof which needs circulation for its survival. The cycle of pain, inflammation, more pain and more tearing becomes unbroken.
This is accompanied by a secondary phenomenon that is the strong pull of the deep flexor tendon. This tendon, having the strongest dynamic attachments to the posterior of the coffin bone, begins its strong pull in the direction of flexion. The counterbalance of the coffin bone is its strong attachment to the hoof wall by the lamellae. With the lamellae failing to adhere to the hoof wall, the flexor begins to rotate the coffin bone downward.
The construction of the extremity in a “digitaped” (or ungulate, i.e., a hooved animal, such as a horse) is such that the skeletal system suspends the animal in a perfectly balanced situation within the skin and the hoof. A disruption of this perfect balance, as well as the pain and the edema associated with the imbalance, allows the flexor to work unchecked, pulling more lamellae free creating more swelling, more bleeding and more pain. The increased edema within the confines of a closed space transmits more pain along the paratenon of the flexor tendon creating a secondary tendonitis.
The laminitis literature implicates a multitude of factors causing this condition: overfeeding, carbohydrate overload, stress, genetics, insulin resistance, injury, and Cushing's syndrome. The cycle as described is pain, inflammation, venous stasis, more inflammation and more pain. The secondary effects of the tendonitis render the animal so incapacitated as to be “paralyzed”. The cycle must be broken either by stopping the edema (stasis), decongesting the arterial flow, or controlling the pain.
Because of the multiplicity of factors implicated in the cause of the condition, the treatment becomes symptomatic on all levels in an effort to salvage the animal.
After having made the association from the human model to the equine model and having had an animal with this chronic recurring problem, the episodes were noted to have an increased intensity and duration with each exacerbation. The one inventor has treated all the episodes which this horse has had with the usual symptomatic treatments: remove the grass, reduce the carbohydrate loads, rocker shoes, pads, analgesics, anti-inflammatories, etc.
During the more recent occasions, in association with the usual symptomatic treatment, the present inventors have added to this the modalities described in this application. The most significant of these is associated with the retrograde massage of the extremities. This type massage starts at the pastern and sequentially moves upward to the cannon bone, metacarpals (knee), ulna-radius to the elbow. This is done in a manner like squeezing a tube of toothpaste from bottom to top. This procedure done on a consistently routine basis reduced the edema and shortened the acute phase interval to the point where the horse was up walking within three to five days. She went on to heal through the re-establishment of the circulation so that the overall long term damage of the condition was minimized. The inventor has recognized that there is less duration, severity and permanent damage when the duration between the appearance of the symptoms of the condition and the consistent application of the retrograde massage methodology is shortened. This is a direct correlation for the one inventor's treatment with the human model.
There is a multitude of compression devices on the market today prescribed for human use. There are, to our knowledge, none on the market for equines. Having used a number of these devices, the most efficacious one to date for humans is the PERISTALTIC PNEUMATIC COMPRESSION DEVICE or similarly applicable device available through the NormaTec Company of Newton Center, Mass. (hereinafter the “NormaTec” and/or PCD device). It has been used on humans with excellent results. We intend to explain, modify and improve on this device to adapt it for use in the equine model for not only improving the condition of laminitis but as a rehabilitative device to improve the circulation in the extremities of horses suffering from the myriad of conditions inflicted upon them by man i.e. navicular disease, bowed tendons, tendonitis, pressure sores, wounds of all types, therapy for fractures, surgeries, post sports injuries, mobilization of exercise-induced, lactic acid build-up, edema of all sorts associated with racing, stocking up, pulmonary congestion, lymphedema, and performance and show injuries in the equine.
The NormaTec device prescribed for humans, when adapted to the equine, must be modified significantly.
The areas where the changes are most apparent from the existing art are:                1. construction of the leg including hoof enveloping garment;        2. chambers equipped with D-rings on Velcro® brand fasteners or similar supplier;        3. apparatus lining with fleece or sheep's skin, removable and washable so as not to transfer body fluids associated with cross contamination, for,                    a. suppression of pressure on tendons,            b. absorption of sweat and body fluids when over an open wound, and,            c. prevention of blistering and pressure sores;                        4. larger bore, delivery tubing to accommodate more volume more rapidly and to decompress more rapidly;        5. an interposed compression device for the initiation of a pressure wave much more rapidly;        6. a different sequence to the pressure wave to ensure no back flow;        7. a time sequence with shorter duration interval for a faster wave;        8. a rapid release methodology for emergency exit (tubing and D-rings); and,Construction        
The NormaTec device or similar supplier is basically a legging. It is a unitary circumferential device. The patient steps into or pulls the legging into or over a secondary garment—a cotton stocking extending from the lower extremity of the foot upward to the thigh. The legging usually consists of four to five pneumatic chambers depending on the size of the patient.
This apparatus needs to be modified to accommodate circumstances unique to the equine application. For example,                a. The apparatus will necessitate being applied as a wrap rather than a contiguous pants-like legging (in humans it must be applied in the recumbent position which is not the case with the equine who stands from the moment of birth). Lifting the leg will not be an option for two reasons:                    1. The condition of laminitis will not accommodate the lifting of one front leg because of the associated pain i.e. the horse's stance is now a tripod. The literature surrounding laminitis regularly refers to the horse's feet being “nailed to the ground”.            2. In the event of an emergency, the boot will need to be removed rapidly, i.e. if the animal goes down or needs other emergency treatment, he will entangle himself and needs to be disengaged rapidly and easily.                        b. Since the horse must stand on its fingertips with a minimally compressible hoof, the design will obviously be modified for various safety and efficacious reasons.        c. Frictional forces on the tendon area from the movement of the garment during inflation/deflation phases can create blistering, soreness and pressure sores. The wrap member will need a fleece or sheep skin type removable lining for the comfort and therapeutic administration of the appropriate pressures and to minimize the contact and heat generated by frictional forces.        d. To secure the wrap member-like device with a quick-release capability, the attachments typically will have to include D-Ring, Velcro® brand fasteners so as to draw upon themselves when inflated, and to avoid opening during the inflation phase. The attachments alternate, left to right, from top to bottom.         e. The tubing will be of a larger bore:                    1. To initiate the flow more quickly.            2. To assure that the deflation cycle is more rapid.                        
The NormaTec device as it exists, has a long inflation time, and a long deflation time (both upwards of three minutes). This is because existing NormaTec tubing, which transfers the air pressure, has very small caliber diameter openings—less than one quarter inch. This restricts the inward and outward flow of the air, prolonging the treatment.
Interposed Compressor or Air Retention Chamber
The devices which exist have no such interposed chamber between the initiation of air flow and the boot. Without this chamber, the flow is restricted and the time interval is longer. This fact coupled with the narrow tubing restricts the volume of the flow of air thus making the rapidity of the inflation and deflation prolonged.
The presence of an intermittent compressor (or holding tank air chamber) in association with the larger tubing will improve the volume of the flow of air on an instantaneous release into the boot and shortens the duration for a five chamber device to a total, in the range of between 15 to 20 sec per complete cycle, unlike the NormaTec device which takes up to 3 minutes to fill and/or complete a cycle. The more rapid the compression/decompression cycle, the more comfortable and tolerable the procedure is. The treatment becomes more efficacious with a more rapid interval. This decreases the edema more rapidly in the extremity thus increasing the blood flow.
The interposed compressor or air chamber will ensure 15 seconds or less as a maximum inflation time and a compression (PH hereinafter) or decompression (PL hereinafter) interval of less than 15 to 30 seconds. This, in conjunction with the larger tubing, will also allow for the more rapid inflow and outflow, shortening the overall duration of the treatment. This more rapid interval of compression and decompression is necessary in an animal of prey, which is genetically geared to “fright or flight”, and will allow for a more rapid accommodation to the device. The animal will tolerate rapid touching and decompression but would not tolerate grabbing and holding.
The NormaTec PCD device or similar device requires either stopping the air flow or interrupting the connection tubing in an emergency situation for decompression and removal of the garment. Because of the narrow tubing, decompression is very slow. The larger the garment, the more volume and the more difficult to deflate rapidly. This coupled with the small diameter of the tubing will create a problem for a horse. A fully inflated cycling garment will not allow the joints to flex since the animal is in a standing position. If the horse were to collapse without the garment deflating quickly enough, a fracture, dislocation or other permanent injuries could easily occur. A quick release valve, with a wide port, will be used to assist in the rapid decompression and quick removal of the compression wrap member, when necessary.
It is our objective through the use of this device to reduce the number and duration of the protracted conditions of laminitis in horses, as well as the vascular and extremity conditions created by equestrian sports, and to alleviate the discomfort. This hopefully will minimize: the extremes of surgical intervention such as cutting the tendon; the use of podiatric devices; and, the all too many cases of euthanasia, by bringing these animals back to soundness again.